词根词缀：-less

【来源及含义】Old English: -leas, from leas, "free from, devoid of, false, feigned"; suffix meaning "lacking"

【同源单词】aimless, artless, avoidless, causeless, ceaseless, charmless

词根词缀：valid-, val-, vale-, -vail, -valent, -valence

【来源及含义】Latin: valere, to be strong, to be well, to be worth; strong; power, strength; and "fare well" [go with strength]

【同源单词】Ab abusu ad usum non valet consequentia, Ab actu ad posse valet illatio, ad valorem, Aeternum vale, ambivalence, ambivalent